IPA: /ˈrɪɡərəs/
KK: /ˈrɪɡərəs/
Strict and demanding, often requiring a lot of effort or discipline. It can also mean very precise or harsh in conditions.
The rigorous training program helped the athletes improve their performance significantly.
Rigorous → It is formed from "rigor" (from Latin "rigor", meaning stiffness or severity) and the suffix "-ous" (meaning full of or characterized by). The word "rigorous" means characterized by strictness or severity.
Think of 'rigor' meaning strictness or severity, and remember that 'rigorous' describes something full of strictness.